The agent for Joe Kennedy said Sunday the family has been told by doctors the pitcher's death might have been the result of an enlarged heart.
Agent Damon Lapa said it will take 6-to-8 weeks for the results of Kennedy's autopsy, pending the completion of toxicology tests.
Kennedy, a journeyman who pitched for three major-league teams in 2007, finishing up the season with Toronto, died at his in-laws' home Friday at age 28.
Kennedy woke up at about 1:15 a.m. Friday and collapsed as he was leaving a bedroom at the home of his wife's parents, Hillsborough County sheriff's spokeswoman Debbie Carter said. Hillsborough County Fire Rescue took Kennedy to Brandon Hospital, where he was pronounced dead.
Kennedy spent seven years in the majors, playing last season with Oakland, Arizona and Toronto. He also spent time with Tampa Bay and Colorado and had a 43-61 career record with a 4.79 ERA in 222 appearances.
Kennedy's death shocked former teammates, managers and executives around Major League Baseball. Kennedy's family -- wife Jami and 1-year-old son Kaige, still lived in the Denver area. According to a report out of Toronto, Jami Kennedy is expecting their second child.
"My wife [Karla] and I were driving down the hill when a coach called and told me. I was just crushed, Rockies manager Clint Hurdle told the Denver Post. "We are so saddened by the loss. I know that Joe was really embracing fatherhood."
"There was never a day when he was in a bad mood. He was always happy, always full of life, always busting your chops," former Rays teammate Aubrey Huff told the St. Petersburg Times. "We came up together with Tampa Bay, and he's one of the few guys I've kept up with.
"He's always been there for me, no matter where he's been. ... I just don't know what to say. It's just heart-wrenching."
Blue Jays president Paul
Godfrey said Toronto was interested in bringing Kennedy back.
"We had every intention to speak to him," he said. "We had him on our list to talk to."
Information from The Associated Press was used in this report.